由博士生德丽亚等撰写的论文A semi-cascade heat pump system for different temperature lifts在Applied Thermal Engineering 2024年第236卷在线发表。论文提出了一类适应大温跨应用场景的半复叠热泵，将传统的单级热泵+复叠热泵进行了系统融合，新系统可以灵活地在单级热泵、复叠热泵和半复叠热泵之间按最高能效切换运行，具有重要的理论意义和应用价值。

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论文摘要：

Conventional cascade heat pumps are widely applied to large temperature lifts between the heat sink and the heat source (ΔT_source-sink). However, this system configuration struggles to maintain energy efficiency over a wide range of operating conditions, especially for small ΔT_source-sink or large temperature lifts on the heat sink side (ΔT_sink). To address this challenge, a novel semi-cascade heat pump system is proposed for flexible operation across varying temperature lifts. The system can operate in three modes, including single-stage mode, conventional cascade mode, and semi-cascade mode with stepped heating. To verify the advantages of multi-mode operation, various conditions are considered for ΔT_source-sink of 20–110 °C and ΔT_sink of 10–100 °C. A steady-state thermodynamic system model using GREATLAB solver is developed and validated. Based on the parameter optimization, the energy performance of each mode is analyzed and mode switching correlations are developed. The results show that the single-stage mode performs best for both small ΔT_source-sink and ΔT_sink, while the conventional cascade mode is suitable for relatively large ΔT_source-sink and small ΔT_sink. The semi-cascade mode maintains high efficiency over a wider range of ΔT_source-sink and ΔT_sink. The novel system achieves up to 22.3 % efficiency improvement versus the conventional cascade system, demonstrating promise for applications with a wide range of temperature lifts.